The aim is to study a specific group of PD patients, carriers of mutations in the glucocerebrosidase (GBA) gene, which is the most common genetic risk factor for PD and is a harbinger of aggressive cognitive and motor decline. Approximately 12-17% of PD patients undergoing DBS are GBA mutation carriers. GBA mutation carriers with PD have a specific phenotype characterized by more significant motor dysfunction and reduced short-term visual memory function compared with their non-GBA counterparts. Thus as GBA mutation carriers have a "signature" phenotype, the investigators hypothesize that these GBA mutation carriers have a unique "signature" of oscillatory activity that can be distinguished from non-mutation carriers during motor activation and during cognitive tasks. Identification of this "signature" will provide critical information that is required to: 1) understand the underlying neurophysiological mechanisms responsible for the aggressive disease course of GBA associated PD, and 2) further develop customized adaptive DBS systems.

Inclusion Criteria:

• undergoing bilateral STN-DBS
• diagnosis of Parkinson's disease

Exclusion Criteria:

• no Parkinson's disease

Patients with Parkinson's disease (PD) with and without mutations in the GBA gene who already have an implanted deep brain stimulator (DBS) device or those patients with PD-GBA mutation carrier who will be undergoing placement of a DBS device using standard technique with sedation and local anesthesia.